Method of changing the composition of iron and steel.



' FORD.

METHOD OF CHANGIN COMPOSITION OF IRON AND STEEL.

PPL AT L D AN A [C 1 ,1 96,767. Patented Sept. 5, 1916.

ml BruceffibraL I zzw awz Q BRUCE FORD, 0F PHILADELPHIA, PENNSYLVANIA.

METHOD OF CHANGING THE COMPOSITION OF IRON AND STEEL.

Specification of Letters Patent.

Application filed January-27, 1914. Serial No. 814,637.

To all whom it may concern:

Be it known that I, BRUCE FORD, a c1t1- zen of the United States, and aresidentof Philadelphia, in the county of Philadelphia and State ofPennsylvania, have invented a certain new and useful Method of Changingthe Composition of Iron and Steel, of which the following is aspecification.

The principal object of the present invention is to provide for quickly,economically and uniformly changing the composition of objects of ironand steel to a substantial depth and to avoid waste of the medium.

In accordance with the present invention the composition of an iron orsteel object is changed by submerging it ina suitably heated medium andlimiting the heat of the medium to a temperature a little below itstemperature of decomposition and locally decomposing a portion of themedium in the vicinity of the object by raising the temperature of theobject above the temperature of decomposition of the medium by electricresistance heating and permitting the object to rapidly absorb themedium as it is decomposed in contact therewith.

The invention further comprises the improvements to be presentlydescribed and finally claimed.

Reference will be made to the accompanying drawings in which isillustrated princi-- pally in section one form of apparatus by means ofwhich the process can be practised. In practising the process inconnection with the apparatus shown in the drawings.

the medium 1 is contained in a suitable receptacle 2 and is heated bycombustion in the furnace or chamber 3. v

3 is a diagrammatic representation of a burner such as may be employedfor burning oil.

4, is a cover for the receptacle and 5 a ventilating hood that-may beemployed, if desired. 6 and 7 areelectrodes properly insulated as at 8and arranged to depend into the medium 1. These electrodes are connectedin the circuit 9 which may be the ,is heated by this electric resistanceheating? secondary circuit an appropriate transformer. The object, 10,of iron or steel to be treated is immersed in the medium 1 and connectedinto the, circuit of thdelectrodes so as to be heated 'byresistance Theobject to a temperature higher than the temperatureof decomposition ofthe medium so that the medium is decomposed in the vicinity of theobject and in contact with it and the medium is therefore rapidlyabsorbed by the object, so that the composition of the object is quicklychanged, While at the same time there is no waste of the medium since itis not decomposed otherwise than locally as above described.

The cross-sectional area of the ends of the object may be reduced asshown at 11, thereby increasing the electrical resistance of the circuitat or near the contacts to provide heat to compensate for heat conductedaway by the contacts or electrodes 6 and 7, Furthermore the ends of theelectrodes are so shaped that the object may be sprung in between themthus facilitating the introduction and removal of the'object. The cover4, of course, can be removed for this pur-' pose. While one object isshown and one set of contacts for each end of the object is shown, it isevident that the electrodes may be provided with a number of separatecontacts arranged side by side and if necessary black and bone black andthe like, or a mixture of these or some of them; or the medium maycontain manganese or silicon in some appropriate form or in fact any ofthese substances which are available in the treatment of iron and steel.

For the sake of further explanation it may be stated that the currentwill vary. However, by way of example, it may be said that for eachsquare inch of the cross-section of the metal to be treated there isrequired approximately two thousand to ten thousand 'amperes and foreach foot in length' of the metal to be treated there is required fromPatented Sept. 5, 1916.

two to five volts, according to the. shape of i the cross-section andthe capacity. of the mefdium for taking away heat, buii'fin any eventoinpo'sition'aiid' the fact tli, he medium ,is-otli'erwise heated to atemperature below its point of decomposition 1s.,product1ve of economyin operation and results.

In using the word quickly in describing the time required for thesubstantiai conversion of the composition of the metal re;

erence is had to time measured in minutes or hours as distinguished fromhours and days and even weeks,

@bviously modifications may be made without departing from the spirit ofthe invention which is not limited in matters of detail or otherwisethan as the prior state of the art may require or as the claims mayindicate.

What I claim is:

1. The process of changing the composition of an iron or steel objectwhich consists in heating a suitable medium from a source of heat otherthan the resistance electric heating hereinafter referred to andlimiting its heat to a temperature below its temperature ofdecomposition, immersing the object in such medium and locallydecomposing the portion of the medium in the vicinity of the object byraising the temperature of the latter above the temperature of themedium and above the temperature of decomposition of the medium byresistance electric heating, and permitting the object to rapidly absorbthe medium as it is decomposed in contact therewith.

2. The process of changing the composition of iron and steel objectswhich consists in heating a suitable medium from a source of heatingother than the resistance electric seer/er heating hereinafter referredto are in. its heat to a less temperature tha 1 its perature ofdecomposition, us a objec in such medium, reducin QI@SF- sectional areaof the ends of the object, rai"- ing the temperature of the medium invicinity er the object above the ten aer of decomposition of the mediumby passa current through the object and its reduc ends, and permittingthe object to ahsoi the medium as it is decomposed in cen therewith.

8. The process of changing the composition of an iron or steel objectwhich consists in heating the object while in contact with a suitablemedium from a source or heat' other than the resistance electric heatmghereinafter referred to and limiting its heat to a temperature below itstemperature of decomposition, and locally decomposing the portion of themedium in the vicinity of the object by raising the temperature of thelatter above the temperature of the medium and above the temperature ofdecomposition of the medium'by resistance electric heating andpermitting the object to rapidly absorb the medium as it is decomposedin contact therewith.

BRUCE FURD.

Witnesses:

C IFFORD K. CAssEL, FRANK E. FRENCH.

